Air purifier and an operating method for the same

ABSTRACT

Disclosed is an air purifier able to maintain the normal state of drive of a disk-shaped humidification filter by controlling the state of rotation of the humidification filter. The air purifier can maintain the normal state of drive of the humidification filter by using a stepping motor and the control unit in order to vary the state of rotation of the humidification filter and thereby remove extraneous material when the humidification filter is rotating abnormally due to extraneous material.

PRIORITY

This application is a Divisional Application of U.S. patent applicationSer. No. 13/577,770; now U.S. Pat. No. 9,127,852; which was filed in theU.S. Patent and Trademark Office on Aug. 8, 2012, as a National PhaseEntry of PCT International Application No. PCT/KR2011/001369 filed Feb.25, 2011, and claims priority to Korean Patent Application No.10-2010-0017174 filed with the Korean Intellectual Property Office onFeb. 25, 2010, and to Korean Patent Application No. 10-2011-0017266filed with the Korean Intellectual Property Office on Feb. 25, 2011, thecontents of each of which is incorporated herein by reference.

BACKGROUND

1. Field of the Invention

The present invention relates to an air purifier and an operating methodthereof, and more particularly, to an air purifier expelling humidifiedair through a humidification filter, and an operating method thereof.

2. Description of the Related Art

In general, an air purifier is a device that filters contaminant dust ormaterials harmful to humans from air, through various filters to providefresh air. A humidification type air purifier, among air purifiers, is adevice using a principle that air purified through various filters ischanged into humidified air when it passes through a humidificationfilter.

Here, water used in a humidification type air purifier, i.e., waterabsorbed into a humidification filter, includes dissolved solids. Thus,mineral components such as magnesium, potassium, or calcium, i.e.,dissolved solids, are absorbed into the humidification filter in anionic state. When purified air passes through the humidification filterby the action of a fan, dissolved solids are formed as white solids inthe humidification filter.

In order to prevent a formation of these white solids, a humidifyingoperation is performed through a plurality of disk-type humidificationfilters mounted on a rotational shaft such that portions thereof areimmersed in a water tank.

However, when foreign objects, or the like, are caught in a spacebetween the disk type humidification filters and the water tank, thehumidification filters may not rotate or may rotate abnormally,resulting in a situation in which the humidification filters cannotprovide moisture in air expelled from the air purifier or thehumidification performance thereof is degraded.

In addition, when the disk type humidification filters are eccentricwith respect to the rotational shaft, they may not be able to rotate dueto various issues.

Namely, a disk constraint state in which the humidification filters donot rotate normally may occur.

When the humidification filters do not rotate, the air purifier isrequired to be stopped to perform a maintenance operation to removeforeign objects caught in the space between the humidification filtersand the water tank.

Namely, an air purifier in which whether or not humidification filtersare rotating normally is detected, and when the humidification filtersare not rotating, foreign objects caught in a space between thehumidification filters and a water tank may be simply removed or a diskconstraint state may be released is required.

SUMMARY

An aspect of the present invention provides an air purifier in which anormal driving state of a disk type humidification filter is maintainedby controlling a rotational condition of the humidification filter, andan operating method thereof.

According to an aspect of the present invention, there is provided anair purifier including: a water tank accommodating water therein andhaving a rotational shaft on which a humidification filter is mounted; adriving source connected to the rotational shaft for rotation thereof; asensing unit installed in the water tank to sense a driving state of thehumidification filter; and a controller connected to the sensing unitand the driving source to control a driving state of the driving sourceaccording to a signal from the sensing unit.

The driving source may be configured as a stepping motor for changing arotational speed or a rotational direction to change torque generatedwhen the humidification filter rotates.

The sensing unit may include: a magnet mounted on the rotational shaftto rotate together therewith; and a magnetic sensor installed in thewater tank such that the magnetic sensor is adjacent to the magnet, andsenses a magnetic field generated by the magnet.

When the humidification filter is driven abnormally, the controller maydrive the driving source to reversely rotate the humidification filteror drive the driving source to repeatedly rotate the humidificationfilter reversely and forwardly in order to increase torque generatedwhen the humidification filter rotates.

According to another aspect of the present invention, there is provideda method for operating an air purifier, including: a) an operation ofrotatably driving a disk type humidification filter; b) a firstdetermination operation of sensing a rotational speed of thehumidification filter through a sensing unit to determine a drivingstate of the humidification filter; and c) an operation of changing therotational speed of the humidification filter to drive thehumidification filter at the changed rotational speed, when thehumidification filter is not driven at a rotational speed controlled bya controller.

In operation c), the rotational speed of the humidification filter maybe reduced to drive the humidification filter at the reduced speed inorder to increase torque generated when the humidification filterrotates.

The method may further include: d) a second determination operation ofsensing a rotational speed of the humidification filter through thesensing unit to determine a driving state of the humidification filter;and e) an operation of changing a rotational direction of thehumidification filter and driving the humidification filter in thechanged direction, when the humidification filter is not driven at arotational speed controlled by the controller.

In operation e), the humidification filter may be rotatably driven in adirection the reverse of the direction in which the humidificationfilter rotates in a normal driving state.

In operation e), the humidification filter may be rotatably driven byrepeatedly changing the rotational direction thereof such that thehumidification filter rotates in the direction the reverse of thedirection in which the humidification filter is driven in the normaldriving state and then in the forward direction.

In operations b) and d), it may be determined whether or not thehumidification filter is rotating at a rotational speed according to apulse signal transmitted to a driving source from the controller whichcontrols the driving source that changes torque generated when thehumidification filter rotates and rotatably drives the humidificationfilter in forward and reverse directions.

The method may further include: f) a third determination operation ofsensing a rotational speed of the humidification filter through thesensing unit to determine a driving state of the humidification filter,after operation e); and g) an operation of stopping driving of thehumidification filter when the humidification filter is not driven at arotational speed controlled by the controller.

The method may further include: a second determination operation ofsensing a rotational speed of the humidification filter through thesensing unit to determine a driving state of the humidification filterafter operation c); and an operation of stopping driving of thehumidification filter when the humidification filter is not driven atthe rotational speed controlled by the controller.

According to another aspect of the present invention, there is provideda method for operating an air purifier, including: a′) an operation ofrotatably driving a disk type humidification filter; b′) a firstdetermination operation of sensing a rotational speed of thehumidification filter through a sensing unit to determine a drivingstate of the humidification filter; and c′) an operation of changing arotational direction of the humidification filter to drive thehumidification filter in the changed rotational direction, when thehumidification filter is not driven at a rotational speed controlled bya controller.

In operation c′), the humidification filter may be rotatably driven in adirection the reverse of the direction in which the humidificationfilter is driven in a normal driving state.

In operation c′), the humidification filter may be rotatably driven byrepeatedly changing the rotational direction thereof such that thehumidification filter rotates in the direction the reverse of thedirection in which the humidification filter is driven in the normaldriving state and then in the forward direction.

The method may further include: d′) a second determination operation ofsensing a rotational speed of the humidification filter through thesensing unit to determine a driving state of the humidification filter;and e′) an operation of changing the rotational speed of thehumidification filter to drive the humidification filter at the changedrotational speed, when the humidification filter is not driven at arotational speed controlled by the controller.

In operation e′), the rotational speed of the humidification filter maybe reduced to drive the humidification filter at the reduced rotationalspeed to increase torque generated when the humidification filterrotates.

In operations b′) and d′), it may be determined whether or not thehumidification filter is rotating at a rotational speed according to apulse signal transmitted to a driving source from the controller whichcontrols the driving source that changes torque generated when thehumidification filter rotates and rotatably drives the humidificationfilter in forward and reverse directions.

The method may further include: f′) a third determination operation ofsensing a rotational speed of the humidification filter through thesensing unit to determine a driving state of the humidification filter,after operation e′); and g′) an operation of stopping driving of thehumidification filter when the humidification filter is not driven at arotational speed controlled by the controller.

The sensing unit may sense a rotational speed of the rotational shaftthrough a signal sensed by a magnetic sensor unit that senses strengthof a magnetic field generated by a magnet rotating together with arotational shaft in which the humidification filter is mounted.

The method may further include: a second determination operation ofsensing a rotational speed of the humidification filter through thesensing unit to determine a driving state of the humidification filterafter operation c′); and a operation of stopping driving of thehumidification filter when the humidification filter is not driven atthe rotational speed controlled by the controller.

According to embodiments of the present invention, when thehumidification filter rotates abnormally due to foreign objects, theforeign objects are removed by changing a rotational condition of thehumidification filter through a stepping motor and a controller, thusmaintaining a normal driving state of the humidification filter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating a configuration of an air purifieraccording to an embodiment of the present invention.

FIG. 2 is a view illustrating a humidifying unit and a controlleraccording to an embodiment of the present invention.

FIG. 3 is a cross-sectional view taken along line X-X′ illustrated inFIG. 2.

FIG. 4 is a cross-sectional view taken along line Y-Y′ illustrated inFIG. 2.

FIGS. 5 and 6 are flow charts illustrating examples of a method foroperating an air purifier according to an embodiment of the presentinvention.

FIGS. 7 and 8 are flow charts illustrating further examples of a methodfor operating an air purifier according to an embodiment of the presentinvention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

Hereinafter, an air purifier according to an embodiment of the presentinvention will be described with reference to the accompanying drawings.

FIG. 1 is a view illustrating a configuration of an air purifieraccording to an embodiment of the present invention.

With reference to FIG. 1, an air purifier 100 according to an embodimentof the present invention includes a water tank 120, a driving source140, a sensing unit 160, and a controller 180.

Meanwhile, the air purifier 100 according to an embodiment of thepresent invention may further include a body case 20, a filter unit 40,an intake unit 60, and a humidifying unit 80.

Hereinafter, first, the body case 20, the filter unit 40, the intakeunit 60, and the humidifying unit 80 will be briefly described, andthen, the water tank 120, the driving source 140, the sensing unit 160,and the controller 180 provided in the air purifier 100 according to anembodiment of the present invention will be described.

The body case 20 having an internal space may include an inlet 22through which ambient air is introduced, and an outlet 24 through whichair introduced through the inlet 22 is expelled. Meanwhile, the bodycase 20 may further include a partition wall 23 dividing the internalspace thereof.

Meanwhile, the filter unit 40 may be disposed in front of the body case20 in an air flow path, and include a plurality of filters. The filterunit 40 serving to purify introduced air may include a pre-processingfilter, a post-processing filter, a high efficiency particulatearresting air (HEPA) filter, an activated carbon filter, and the like.

The intake unit 60 serves to allow ambient air to be introduced into thebody case 20 and expelled therefrom, and to this end, the intake unit 60may include an intake fan 62.

Namely, when the intake fan 62 is driven, ambient air is introducedthrough the inlet 22 of the body case 20, passes through the filter unit40, and is then discharged through the outlet 24.

The humidifying unit 80 is disposed in a flow path of introduced air toprovide moisture to air being expelled. To this end, the humidifyingunit 80 may include a plurality of disk type humidification filters 110,the water tank 120 providing moisture to the humidification filters 110,and the driving source 140 generating driving force to rotatably drivethe humidification filters 110.

Hereinafter, the air purifier 100 according to an embodiment of thepresent invention will be described with reference to FIGS. 2 through 4.

FIG. 2 is a view illustrating a humidifying unit and a controlleraccording to an embodiment of the present invention. FIG. 3 is across-sectional view taken along line X-X′ illustrated in FIG. 2. FIG. 4is a cross-sectional view taken along line Y-Y′ illustrated in FIG. 2.

With reference to FIGS. 2 through 4, the humidification filters 110 areformed to have a circular disk-like shape, and lower end portions of thehumidification filters 110 may be immersed in the water tank 120 suchthat moisture can be supplied to the surfaces of the humidificationfilters 110.

The water tank 120 has water accommodated therein and may have arotational shaft 122 in which the humidification filters 110 aremounted. Namely, the humidification filters 110 are mounted in therotational shaft 122 and are rotated together with the rotational shaft122 when the rotational shaft 122 rotates.

Accordingly, moisture may be constantly supplied to the surfaces of thehumidification filters 110 from the water tank 120.

Also, the rotational shaft 122 is rotatably mounted in an installationstand 124 of the water tank 120.

Meanwhile, the humidification filters 110 mounted on the rotationalshaft 122 of the water tank 120 are disposed such that thehumidification filters 110 are spaced apart by a certain interval fromside walls of the water tank 120.

Here, when foreign objects, or the like, are caught in a space 120 abetween the humidification filters 110 and the water tank 120, thehumidification filters 110 cannot be driven normally. Namely, thehumidification filters 110 may not be rotated or may be driven to berotated and repeatedly stopped due to foreign objects.

The driving source 140 is connected to the rotational shaft 122 torotate the rotational shaft. Namely, the driving source 140 generatesdriving force for driving rotation of the humidification filters 110,and the rotational shaft 1122 is rotated according to driving of thedriving source 140, and accordingly, the humidification filters 110installed in the rotational shaft 122 may be rotated cooperatively.

Meanwhile, the driving source 140 may be configured as a stepping motorfor changing torque generated during driving or a rotational direction.

Since the driving source 140 is configured as a stepping motor, arotational speed and torque generated when the driving source 140 isdriven may be changed. Namely, when the rotational speed increases,torque generated when the humidification filters 110 are driven isreduced, and when the rotational speed is reduced, torque generated whenthe humidification filters 110 are driven is increased.

Also, since the driving source 140 is configured as a stepping motor, itcan drive the rotational shaft 122 in forwards and backwards directions.

The sensing unit 160 is installed in the water tank 120 in order tosense a driving state of the humidification filters 110.

Meanwhile, the sensing unit 160 may include, for example, a magnet 162and a magnetic sensor 164.

The magnet 162 may be mounted on the rotational shaft 122 such that itmay be rotated together therewith. Namely, the magnet 162 may beinserted into a fastening recess 122 a formed in the rotational shaft122 so as to be rotated together with the rotational shaft 122 when therotational shaft 122 rotates.

The magnet 162 is an annular permanent magnet. For example, the magnet162 may be installed as a single magnet in the rotational shaft 122. Inanother example, as shown in FIG. 2, the magnet 162 may be installed onthe rotational shaft 122 such that S poles 162 a and N poles 162 bthereof are arranged to be contiguous at equal intervals.

The magnetic sensor 164 is installed to be adjacent to the magnet 162 inthe water tank 120 in order to sense a magnetic field generated by themagnet 162.

Namely, the magnetic sensor 164 is installed on the installation stand124 of the water tank 120. In detail, an installation recess 124 a isformed in the installation stand 124 to allow the rotational shaft 122to be rotatably installed, and a bearing 126 may be insertedly mountedin the installation recess 124 a to allow the rotational shaft 122 to besmoothly rotated.

Meanwhile, the installation recess 124 a may include a mounting recess124 b in which the magnetic sensor 164 is mounted to be opposed to themagnet 162 mounted on the rotational shaft 122.

In other words, the magnetic sensor 164 is installed in the mountingrecess 124 b and senses a change in a magnetic field generated by themagnet 162 rotated together with the rotational shaft 122, namely, aspeed of a change in a magnetic field with respect to S poles and Npoles sensed according to a change in a rotational speed of the S poles162 a and the N poles 162 b.

Meanwhile, the magnetic sensor 164 may be connected to the controller180, and a signal with respect to a change in a magnetic field sensed bythe magnetic sensor 164 may be output to the controller 180.

The controller 180, connected to the sensing unit 160 and the drivingsource 140, controls a driving condition of the driving source 140according to a signal from the sensing unit 160.

Namely, after the controller 180 determines whether or not thehumidification filter 110 is being normally driven according to a signalfrom the sensing unit 160, the controller 180 may control the drivingsource 140 to change a rotational speed and rotational direction thereofto drive the humidification filter 110.

In detail, while the humidification filter 110 is being rotatablydriven, namely, while the humidification filter 110 is being rotatablydriven in a normal driven state, when foreign objects, or the like, arecaught in the space 120 a between the humidification filter 110 and thewater tank 120, the humidification filter 110 cannot rotate normally.

Namely, the humidification filter 110 will not rotate, may rotate and bestopped repeatedly, or may rotate at a reduced rotational speed. In sucha case, the controller determines that the humidification filter 110 isrotating abnormally, based on a signal output from the sensing unit 160.

Meanwhile, the normal driving state of the humidification filter 110refers to a state in which the humidification filter 110 rotates whenthe humidifying unit 80 is driven to perform a humidification function,and in this case, the humidification filter 110 is driven to rotate at aspeed of 15 rpm to generate torque of 1 kgf·cm.

Thereafter, the controller 180 may reduce the rotational speed of thedriving source 140, i.e., stepping motor, to increase torque generatedwhen the humidification filter 110 rotates.

In other words, the driving source 140 drives the humidification filter110 at a speed of 4 rpm to generate torque of 2 kgf·cm. Here, thedriving source 140 is driven according to a pulse signal from thecontroller 180 to drive the humidification filter 110.

The driving source 140 is driven to drive the humidification filter 110with torque increased by the humidification filter 110 during a certainperiod of time (e.g., 60 seconds), and at this time, the controller 180determines a driving condition of the humidification filter 110 througha signal with respect to a rotational speed sensed by the sensing unit160.

Namely, the humidification filter 110 is required to be driven at aspeed of 4 rpm to generate torque of 2 kgf·cm by a pulse signaltransmitted from the driving source 140.

Here, however, if a signal transmitted to the controller 180 from thesensing unit 160 is a signal indicating that the humidification filter110 is not rotating, is rotating and is stopping repeatedly, or isrotating at a speed lower than 4 rpm, the controller 180 determines thatthe humidification filter 110 is rotating abnormally. Namely, thecontroller 180 determines that the humidification filter 110 is in aconstraint state.

Thereafter, the controller 180 controls the driving source 140 to rotatethe humidifying unit 110 in a reverse direction during a certain periodof time (e.g., 60 seconds).

Meanwhile, when it is determined the humidification filter 110 isrotating normally according to the signal transmitted to the controller180, namely, when it is determined that the humidification filter 110 isdriven at a speed of 4 rpm to generate torque of 2 kgf·cm according tothe pulse signal from the controller 180, the controller 180 controlsthe driving source 140 to drive the humidification filter 110 in thenormal driving state.

When the humidifying unit 110 is controlled to be rotated in a reversedirection by the controller 180, the controller 180 senses whether ornot the humidification filter 110 is rotated normally in the reversedirection through the sensing unit 160 after the lapse of a certainperiod of time.

If foreign objects caught in the space 120 a between the humidificationfilter 110 and the water tank 120 are removed according to the reverserotation of the humidifying unit 110 so the humidification filter 110 isdriven normally in the reverse direction according to a signal from thecontroller 180, the controller 180 rotates the humidification filter 110to be rotated in the normal driving state (e.g., the humidificationfilter 110 rotates at a speed of 15 rpm).

Meanwhile, when foreign objects caught in the space 120 a between thehumidification filter 110 and the water tank 120 are not removedaccording to the reverse rotation of the humidification filter 110, thehumidification filter 110 cannot rotate normally in the reversedirection. Here, the controller 180 stops the driving of thehumidification filter 110.

Thereafter, the controller 180 may display the abnormal rotation stateof the humidification filter 110 on a display unit (not shown).

As described above, when the humidification filter 110 rotatesabnormally through the driving source 140 configured as a stepping motorand the controller 180 due to foreign objects, the foreign objects areremoved by changing the rotational condition of the humidificationfilter 110, thereby maintaining the normal driving state of thehumidification filter 110.

Namely, since the controller 180 controls the driving source 140according to a signal with respect to the rotational condition of thehumidification filter 110 sensed by the sensing unit 160, when thehumidification filter 110 is driven abnormally due to foreign objectscaught in the space 120 a between the humidification filter 110 and thewater tank 120, the controller 180 may remove the foreign objects bychanging the rotational condition of the humidification filter 110,whereby the humidification filter 110 can be maintained in the normaldriving state.

Accordingly, eventually, humidification performance of the air purifier100 can be enhanced.

A method for operating an air purifier 100 according to an embodiment ofthe present invention will be described with reference to theaccompanying drawings.

Here, the same components as those described above will be described byusing the same reference numerals.

FIGS. 5 and 6 are flow charts illustrating examples of a method foroperating an air purifier according to an embodiment of the presentinvention.

With reference to FIGS. 5 and 6, first, the humidification filter 110 isrotatably driven in a normal driving state (e.g., at a speed of 15 rpmto generate torque of 1 kgf·cm) (S110). Here, the sensing unit 160senses a rotational condition of the humidification filter 110, namely,a rotational condition (e.g., a rotational speed) of the rotationalshaft 122 rotating together with the humidification filter 110 (S120).Thereafter, the sensing unit 160 outputs a signal with respect to therotational condition of the humidification filter 110 to the controller180.

The controller 180 determines whether or not the humidification filter110 is rotating at a rotational speed according to a signal transmittedfrom the controller 180, through a signal from the sensing unit 160(S130).

When it is determined that the humidification filter 110 is rotating inthe normal driving state, the controller 180 controls the driving source140 such that the humidification filter 110 is continuously rotating inthe normal driving state (e.g., at the speed of 15 rpm to generatetorque of 1 kgf·cm) (S110).

However, when it is determined that the humidification filter 110 isrotating abnormally, the controller 180 controls the driving source 140,i.e., the stepping motor, during a certain period of time (e.g., 60seconds) to reduce the speed of the humidification filter 110 andincrease torque generated when the humidification filter 110 rotates(S140).

Namely, the controller 180 controls the driving source 140 to rotate thehumidification filter 110, for example, at a speed of 4 rpm to generatetorque of 2 kgf·cm for 60 seconds so that foreign objects caught in thespace 120 a between the humidification filter 110 and the water tank 120can be removed.

As described above, when the humidification filter 110 is rotatablydriven, the sensing unit 160 senses a rotational condition of thehumidification filter 110, namely, a rotational condition (e.g., arotational speed of 0 of the rotational shaft 122 rotating together withthe humidification filter 110 (S150)). Thereafter, the sensing unit 160outputs a signal with respect to the rotational condition of thehumidification filter 110 to the controller 180.

Thereafter, the controller determines again whether or not thehumidification filter 110 is rotating at the rotational speed (i.e., 4rpm) according to the signal transmitted from the controller 180, basedon a signal from the sensing unit 160 (S160).

When foreign objects are removed by the humidification filter 110rotating to generate increased torque, the humidification filter 110 canbe driven at the rotational speed, i.e., at the speed of 4 rpm,according to the signal from the controller 180. In this case, thecontroller 180 drives the humidification filter 110 to be driven in thenormal driving state (e.g., at the speed of 15 rpm to generate torque of1 kgf·cm) (S110).

However, when foreign objects are not removed, the humidification filter110 cannot rotate at the rotational speed (e.g., at the speed of 4 rpm)according to the signal from the controller 180. Then, the controller180 determines that the humidification filter 110 is driven abnormally,based on the signal from the sensing unit 160.

Here, when it is determined that the humidification filter 110 is drivenabnormally, as shown in FIG. 5, the controller 180 controls the drivingsource 140 to stop rotational driving of the humidification filter 110after operation S160 (operation S199), and thereafter, the controller180 displays the abnormal rotation state of the humidification filter110 on a display unit (not shown).

Or, as shown in FIG. 6, the controller 180 controls the driving source140 to rotate the humidification filter 110 for a certain period of time(e.g., 60 seconds) such that foreign objects caught in the space 120 abetween the humidification filter 110 and the water tank 120, which havenot been removed by the humidification filter 110 rotating withincreased torque, can be removed according to the rotation of thehumidification filter 110 (S170).

Here, in operation S170, the humidification filter 110 may rotate in adirection the reverse of the direction in which the humidificationfilter 110 is driven in the normal driving state. Alternatively, inoperation S170, the humidification filter 110 may be driven in thedirection the reverse of the direction in which the humidificationfilter 110 rotates in the normal driving state, and rotates reversely inthe reverse direction so as to rotate in the same forward direction asthe rotational direction of the normal driving state. Here, as for therotational direction of the humidification filter 110, thehumidification filter 110 may rotate alternately repeatedly in thereverse direction and the forward direction for a certain period oftime.

After the humidification filter 110 rotates for a certain period of timethrough the process as described above in operation S170, the controller180 senses a rotational condition of the humidification filter 110through the sensing unit 160 in order to determine whether or not thehumidification filter 110 has rotated normally (S180).

Thereafter, through a signal from the sensing unit 160, the controller180 determines whether or not the humidification filter 110 is drivennormally, namely, whether or not the humidification filter 110 isrotating at the rotational speed (e.g., at 4 rpm in the reversedirection) according to the signal from the controller 180 (S190).

When it is determined that the humidification filter 110 is drivennormally, the controller 180 controls the driving source 140 to drivethe humidification filter 110 in the normal driving state (S110).

However, when it is determined that the humidification filter 110 isdriven abnormally, the controller 180 controls the driving source 140 tostop the rotational driving of the humidification filter 110 (S199), anddisplays the abnormal rotation state of the humidification filter 110 onthe display unit (not shown).

As described above, when the humidification filter 110 rotatesabnormally due to foreign objects, the foreign objects are removed bychanging the rotational condition of the humidification filter 110through the driving source 140 configured as a stepping motor and thecontroller 180, thereby maintaining the humidification filter 110 in thenormal driving state.

Namely, when the humidification filter 110 is driven abnormally due toforeign objects caught in the space 120 a between the humidificationfilter 110 and the water tank 120, the controller 180 controls thedriving source 140 according to a signal with respect to the rotationalcondition of the humidification filter 110 sensed by the sensing unit160 to change the rotational condition of the humidification filter 110to remove foreign objects, thus maintaining the normal driving state ofthe humidification filter 110.

FIGS. 7 and 8 are flow charts illustrating other examples of a methodfor operating an air purifier according to an embodiment of the presentinvention.

With reference to FIGS. 7 and 8, first, the humidification filter 110 isrotatably driven in a normal driving state (e.g., at a speed of 15 rpmto generate torque of 1 kgf·cm) (S210). Here, the sensing unit 160senses a rotational condition of the humidification filter 110, namely,a rotational condition (e.g., a rotational speed) of the rotationalshaft 122 rotating together with the humidification filter 110 (S220).Thereafter, the sensing unit 160 outputs a signal with respect to therotational condition of the humidification filter 110 to the controller180. The controller 180 determines whether or not the humidificationfilter 110 is rotating at a rotational speed according to a signaltransmitted from the controller 180, through a signal from the sensingunit 160 (S230).

When it is determined that the humidification filter 110 is rotating inthe normal driving state, the controller 180 controls the driving source140 such that the humidification filter 110 continuously rotates in thenormal driving state (e.g., at the speed of 15 rpm to generate torque of1 kgf·cm) (S210).

However, when foreign objects are not removed, the humidification filter110 cannot rotate at the rotational speed (e.g., at the speed of 15 rpm)according to the signal from the controller 180. Then, the controller180 determines that the humidification filter 110 is being drivenabnormally, based on the signal from the sensing unit 160.

Thereafter, the controller 180 controls the driving source 140 to changethe rotational direction of the humidification filter 110 and rotate thehumidification filter 110 for a certain period of time (e.g., 60seconds) such that foreign objects caught in the space 120 a between thehumidification filter 110 and the water tank 120, which have not beenremoved by the humidification filter 110 rotating with increased torque,can be removed according to the rotation of the humidification filter110 (S240).

Here, in operation S240, the humidification filter 110 may rotate in adirection the reverse of the direction in which the humidificationfilter 110 is driven in the normal driving state, such that foreignobjects caught in the space 120 a between the humidification filter 110and the water tank 120 can be removed according to the rotation of thehumidification filter 110.

Or, in operation S240, the humidification filter 110 have been in thedirection the reverse of the direction in which the humidificationfilter 110 rotates in the normal driving state, and the rotationaldirection of the humidification filter 110 is changed to the forwarddirection such that foreign objects caught in the space 120 a betweenthe humidification filter 110 and the water tank 120 can be removedaccording to the rotation of the humidification filter 110. Here, thehumidification filter 110 may rotate alternately repeatedly in thereverse direction and the forward direction for a certain period oftime.

After the humidification filter 110 rotates for a certain period of timethrough the process as described above in operation S240, the controller180 senses a rotational condition of the humidification filter 110through the sensing unit 160 in order to determine whether or not thehumidification filter 110 has rotated normally (S250).

Thereafter, through a signal from the sensing unit 160, the controller180 determines whether or not the humidification filter 110 is drivennormally, namely, whether or not the humidification filter 110 isrotating at the rotational speed (e.g., at 15 rpm in the reversedirection) according to the signal from the controller 180 (S260).

When foreign objects are removed by the humidification filter 110, thehumidification filter 110 is driven at the rotational speed, i.e., atthe speed of 15 rpm, according to the signal from the controller 180. Inthis case, the controller 180 drives the humidification filter 110 to bedriven in the normal driving state (e.g., at the speed of 15 rpm togenerate torque of 1 kgf·cm) (S210).

Here, when it is determined that the humidification filter 110 is drivenabnormally, as shown in FIG. 7, the controller 180 controls the drivingsource 140 to stop rotational driving of the humidification filter 110after operation S260 (S299), and thereafter, the controller 180 maydisplay the abnormal rotation state of the humidification filter 110 ona display unit (not shown).

Or, when it is determined that the humidification filter 110 is rotatingabnormally, as shown in FIG. 8, after operation S260, the controller 180controls the driving source 140, i.e., the stepping motor, during acertain period of time (e.g., 60 seconds) to reduce the speed of thehumidification filter 110 and increase torque generated when thehumidification filter 110 rotates (S270).

Namely, the controller 180 controls the driving source 140 to rotate thehumidification filter 110, for example, at a speed of 4 rpm to generatetorque of 2 kgf·cm for 60 seconds so that foreign objects caught in thespace 120 a between the humidification filter 110 and the water tank 120can be removed.

As described above, when the humidification filter 110 is rotatablydriven, the sensing unit 160 senses a rotational condition of thehumidification filter 110, namely, a rotational condition (e.g., arotational speed of 0 of the rotational shaft 122 rotating together withthe humidification filter 110 (S280). Thereafter, the sensing unit 160outputs a signal with respect to the rotational condition of thehumidification filter 110 to the controller 180.

Thereafter, the controller determines again whether or not thehumidification filter 110 is rotating at the rotational speed (i.e., 4rpm) according to the signal transmitted from the controller 180, basedon a signal from the sensing unit 160 (S290).

When it is determined that the humidification filter 110 is being drivennormally, the controller 180 controls the driving source 140 to drivethe humidification filter 110 in the normal driving state (S210).

However, when it is determined that the humidification filter 110 isbeing driven abnormally, the controller 180 controls the driving source140 to stop the rotational driving of the humidification filter 110(S299), and displays the abnormal rotation state of the humidificationfilter 110 on the display unit (not shown).

As described above, when the humidification filter 110 rotatesabnormally due to foreign objects, foreign objects are removed bychanging the rotational condition of the humidification filter 110through the driving source 140 configured as a stepping motor and thecontroller 180, thereby maintaining the humidification filter 110 in thenormal driving state.

Namely, when the humidification filter 110 is driven abnormally due toforeign objects caught in the space 120 a between the humidificationfilter 110 and the water tank 120, the controller 180 controls thedriving source 140 according to a signal with respect to the rotationalcondition of the humidification filter 110 sensed by the sensing unit160 to change the rotational condition of the humidification filter 110to remove foreign objects, thus maintaining the normal driving state ofthe humidification filter 110.

Accordingly, eventually, humidification performance of the air purifier100 can be enhanced.

While the present invention has been shown and described in connectionwith the embodiments, it will be apparent to those skilled in the artthat modifications and variations can be made without departing from thespirit and scope of the invention as defined by the appended claims.

What is claimed is:
 1. A method for operating an air purifier, themethod comprising: a) an operation of rotatably driving a disk typehumidification filter using a driving source; b) a first determinationoperation of sensing a rotational speed of the humidification filterthrough a sensing unit to determine a driving state of thehumidification filter; and c) an operation of changing the rotationalspeed of the humidification filter to drive the humidification filter atthe changed rotational speed using a controller, when the humidificationfilter is not driven at a rotational speed controlled by the controller,wherein the controller is connected to the sensing unit and the drivingsource to control a driving state of the driving source according to asignal from the sensing unit.
 2. The method of claim 1, wherein inoperation c), the rotational speed of the humidification filter isreduced to drive the humidification filter at the reduced speed in orderto increase torque generated when the humidification filter rotates. 3.The method of claim 2, further comprising: d) a second determinationoperation of sensing a rotational speed of the humidification filterthrough the sensing unit to determine a driving state of thehumidification filter; and e) an operation of changing a rotationaldirection of the humidification filter and driving the humidificationfilter in the changed direction, when the humidification filter is notdriven at a rotational speed controlled by the controller.
 4. The methodof claim 3, wherein in operation e), the humidification filter isrotatably driven in a direction the reverse of the direction in whichthe humidification filter rotates in a normal driving state.
 5. Themethod of claim 3, wherein in operation e), the humidification filter isrotatably driven by repeatedly changing the rotational direction thereofsuch that the humidification filter rotates in the direction the reverseof the direction in which the humidification filter is driven in thenormal driving state and then in the forward direction.
 6. The method ofclaim 3, wherein in operations b) and d), it is determined whether ornot the humidification filter is rotating at a rotational speedaccording to a pulse signal transmitted to a driving source from thecontroller which controls the driving source that changes torquegenerated when the humidification filter rotates and rotatably drivesthe humidification filter in forward and reverse directions.
 7. Themethod of claim 3, further comprising: f) a third determinationoperation of sensing a rotational speed of the humidification filterthrough the sensing unit to determine a driving state of thehumidification filter, after operation e); and g) an operation ofstopping driving of the humidification filter when the humidificationfilter is not driven at a rotational speed controlled by the controller.8. The method of claim 1, further comprising: a second determinationoperation of sensing a rotational speed of the humidification filterthrough the sensing unit to determine a driving state of thehumidification filter after operation c); and an operation of stoppingdriving of the humidification filter when the humidification filter isnot driven at the rotational speed controlled by the controller.